The present invention is directed to a exhaust cleaning apparatus for cleansing fume laden air such as that rising form cooking equipment and/or other work equipment and particularly to an exhaust hood apparatus adapted to be combined with auxiliary enhancement devices including a water wash unit, a compensating air supply and the like for removing foreign matter from fume laden air and discharging environmentally clean air from the exhaust apparatus.
Exhaust hood apparatus is widely used for cleansing of the grease and particle laden air generated by a cooking surface and particularly such as that used in fast food restaurants for deep frying and cooking of product. Various exhaust hood units have been developed for cleansing of the air of particles and general foreign matter. The hood units may be formed with direct mechanical filter systems, with water wash systems and with a combination of mechanical filter systems and water wash systems.
A high satisfactory non-water wash and direct mechanical filter exhaust system is shown in U.S. Pat. No. 4,047,519 assigned to the present assignee of this application. In this and other systems, the fume laden air is passed directly upwardly into and through a mechanical filter arrangement for removing of the foreign matter as the result of the interengagement of the air with one or more mechanical filtering units. A significant and distinct improvement in the functioning of the systems results from the use of a compensating air stream generated by introducing an untempered outside or other air stream into the unit. The compensating airstream is introduced into the hood structure opposite the side of the hood housing the filter unit. THe stream is directed upwardly into the filter, and assists movement of the fume laden air upwardly from the cooking surface into and through the filter. Although various exhaust hoods have been suggested in this variety, the above patent discloses a particularly unique and highly satisfactorily system providing efficient cleansing of the air.
Under certain circumstances, it has been found that under certain conditions the exhausted air may still contaim some foreign matter, and does not provide optimum cleaning. One satisfactory system using a water wash for washing of the air with water to remove the foreign matter is shown in the co-pending application of Strege et al entitled "Exhaust Hood Apparatus For Cleansing Of Exhaust Fluid" which was filed on June 17, 1986 and is assigned to a common assignee with this application. As more fully disclosed in such application, the fume and foreign particle laden air rising from the cooking equipment or other work surface rises upwardly into the exhaust hood. tHe air is directed into a downwardly extending inlet passageway into a water wash unit located to one side of the exhaust hood. THe inlet passageway is a converging passageway for accelerating of the air flow into the water wash mechanism. The water wash unit includes a bath of water forming the bottom wall between the inlet passageway and a reverse upwardly directed water wash chamber. The water wash chamber is provided with a plurality of nozzles for generating a water wash spray with the fume laden air rising upwardly therethrough. A removable baffle unit is mounted within the upper end of the water wash unit exhaust passageway for rapid and effective cleansing of the air of all fume and foreign particles. In passing through the water spray, the grease and other foreign matter in the air is significantly removed and the water drops downwardly into the water bath for cleansing and recycling. The final baffle unit functions to remove the foreign matter which is not removed by the water wash as such. Various other water wash systems are disclosed in various other prior art patents submitted in the above application as well as in other prior art patents. Although the prior art widely uses spray nozzle, a spray environment or water falls for washing of the air had been suggested such that the high velocity stream engaging a water bath can aggitate the upper surface of the water to result in the mixing the the water and the air to provide a cleansing of the air. In such a system, the inlet passageway tot he water wash system includes a laterally directed baffle plate for varying of the opening of the inlet into the water wash and controlling of the size of the jet or the air directed into engagement with theater bath. The air is directed from the bath through a curved passageway for cleansing of the air. The above patents disclose similar water wash unit. U.S. Pat. No. 4,011,082 also discloses a compensating air stream specially constructed for assisting in movement of the fume laden air into t he water wash unit similar tot he compensating hood. The theory and functioning corresponds to that applied to the conventional nonwater discussed U.S. Pat. Nos. 3,978,777 and 4,047,519.
Although mechanical filter systems and the water wash system, particularly such as disclosed in the above patents and application of the present assignee, provided an effective and improved cleansing of the air, there is a continuing demand and need for a versatile design which can be incorporated into anyone of the several desired systems depending on the particular job specification and requirements, at a competitive cost efficient construction. The combination of the water wash and the special baffle unit may increase the cost significantly above that of a simple exhaust system. Although other water wash systems have been suggested, they do not provide the desired improved cleansing and may require even more complicated and expensive mechanisms for cleansing of the air and the like.
There is therefore a continuing demand and need for a basic exhaust hood adapted for direct use as well as improved water wash systems, with or without compensation air system, for cleansing of exhaust air from working areas and particularly cooking equipment. The exhaust hood must provide a relatively simple and cost effective air cleansing apparatus. The apparatus of course should also be particularly adapted for minimum maintenance including simple and reliable means for cleansing of the surfaces within the exhaust passageways.